The present invention relates to bicycle seat posts having adjustable heights.
Most bicycles include a seat post for supporting the seat above the frame. Seat posts are commonly inserted into the seat tube of the bicycle frame and secured in place by a binder bolt. The height of the seat can be adjusted to accommodate riders of various sizes by loosening the binder bolt, sliding the seat post relative to the seat tube, and re-tightening the binder bolt. It can be appreciated that this adjustment to the seat height must be done with the bicycle in a stationary position, with the rider off the bicycle.
In certain situations, it is desirable to adjust the height of a seat while the bicycle is being ridden. For example, in certain off-road riding situations, it is beneficial to lower the seat in order to lower the center of gravity of the rider. This is often advantageous when riding the bicycle at high speeds (e.g., downhill) over bumpy terrain. After the downhill bumpy terrain, it is often desirable to raise the seat back to its original position so that the rider can comfortably sit on the seat and efficiently pedal the bicycle.
In order to satisfy the need for adjusting the seat height while riding, it is known to provide seats that can be adjusted on the fly. For example, it is known to make the seat post from two telescoping members that are coupled by a threaded rod driven by an electric motor. The position of the seat can be adjusted by actuating the motor and turning the threaded rod. Such a system is disclosed in U.S. Pat. No. 6,050,585. Alternatively, it is known to bias the telescoping tubes to an extended position by a spring (e.g., a mechanical or air spring). A locking mechanism (e.g., a hydraulic lock) can be used to selectively secure the height of the seat at the desired position.